The former X Factor judge then went onto suggest Meghan Markle feels "so humiliated [and] so embarrassed" by her father's actions.
Typically, members of the royal family stay away from political discourse and so the Senator quickly deleted her tweet.
She continued: "My father is not an embarrassment for loving his daughter. Act like a humanitarian, act like a woman". "The Royals are an embarrassment for being so cold", Grant wrote on Tuesday.
The Duchess of Sussex is said to be returning to her native country to visit friends and family alone as fans speculate over her dad and sister.
12 new moons of Jupiter discovered, including collision-prone oddity
Jupiter's biggest moon, Ganymede, also has an underground salt ocean - although this ocean may be too salty to be habitable. They are also believed to be fragments of a larger moon that was broken apart and take just under a year to circle Jupiter.
The Duchess of Sussex will apparently take the trip without the Duke of Sussex and plans to visit friends and family before returning for an official visit with her husband in 2019.
Issues among the newlywed's family have been widely reported and it's not the first time her half-sister has attacked her online. "She's learning the hard way that you can't trust anyone outside the narrow circle", said Crown historical consultant and royal biographer, Robert Lacey.
"I have already expressed a message and that is for them all to shut up". Is the Duchess distancing herself from them because of their antics, or are their antics the result of Meghan settling into her new life? "I don't like the one I'm seeing now", he said during the interview. "This one isn't even a stage smile ― this is a pained smile".
According to US Weekly, the newlyweds are also planning a trip across the pond together in spring of 2019, and Meghan "is looking forward to introducing Harry to everything she loves about the US".
The dress, which is only available on Nonie's website, also comes in black and retails for $1,085 so anyone who's got that kind of cash lying around and wants to be just like Megs, hop to it!